From the Guidelines
In patients with low superior mesenteric artery (SMA) and suspected acute mesenteric ischemia due to embolism, initial therapy should prioritize rapid restoration of inline arterial flow to the affected bowel through endovascular interventions, such as aspiration embolectomy, to minimize morbidity and mortality. The diagnosis of acute mesenteric ischemia should be suspected in patients with sudden, severe abdominal pain and high thromboembolic risk, such as those with atrial fibrillation 1. CT angiography (CTA) is crucial in demonstrating an occlusive filling defect in the proximal SMA, characteristic of arterial embolism 1.
Key considerations in managing low SMA with suspected embolic occlusion include:
- Rapid volume resuscitation, empiric antibiotic therapy, and anticoagulation to support the patient and prevent further complications 1
- Endovascular interventions, such as aspiration embolectomy, as the initial approach to restore blood flow, given their high technical success rates and lower morbidity compared to open surgery [1, @5@]
- Awareness that up to 70% of patients may eventually require surgical intervention for bowel resection and/or diversion, despite initial endovascular management [@7@]
- The importance of anticoagulation therapy in patients undergoing aspiration embolectomy, as seen in a retrospective study with 100% survival at 12 months [@8@]
The choice between endovascular and surgical approaches should be guided by the patient's clinical presentation, the availability of expertise, and the potential for minimizing morbidity and mortality. Endovascular interventions are associated with improved short-term mortality rates compared to surgical management, as evidenced by a systematic review and meta-analysis showing a lower 30-day mortality with endovascular therapy [@5@].
From the Research
Definition and Causes
- Low superior mesenteric artery (SMA) can refer to a condition where the SMA is compressed or obstructed, leading to various symptoms and complications 2, 3.
- The SMA syndrome, also known as Wilkie's syndrome, is an obstruction of the duodenum caused by extrinsic compression between the SMA and the aorta 2.
- Traumatic injuries to the mesenteric vessels, including the SMA, are rare and often lethal, posing challenges in diagnosis and management 4.
Symptoms and Diagnosis
- Symptoms of low SMA can include postprandial abdominal pain, nausea and vomiting, early satiety, anorexia, and weight loss 2, 3.
- Diagnostic modalities for SMA syndrome include computed tomography (CT) and ultrasonography, which can assess SMA mobility and duodenum passage 2.
- CT scans can also be used to diagnose superior mesenteric artery embolism, demonstrating enhancement of the SMA roots and non-enhanced filling defect in the more distal part of the artery 5.
Treatment and Management
- Initial treatment for SMA syndrome is usually conservative, including postural change, gastroduodenal decompression, and nutrient management, with success rates of 70%-80% 2.
- If conservative therapy fails, surgical treatment, such as laparoscopic duodenojejunostomy, is recommended, with success rates of 80%-100% 2.
- For patients with asymptomatic or mildly symptomatic nutcracker syndrome, conservative treatment with a focus on weight regain is recommended 3.
- Operative techniques, including endovascular techniques, can be used to treat mesenteric ischemia, including acute and chronic ischemia 6.